نبذة مختصرة : Electrochemical production of green hydrogen applying earth-abundant and cheap materials as electrocatalysts of water electrolyzers, will play an important role in energy transition, besides to boost the development of more sustainable processes in the chemical industry sector.Due to this context, this work proposes the development of alternative cathode, for the replacement of platinum as catalyst of hydrogen evolution reaction (HER). The focus concerned the application of promising discovered materials in an anion exchange membrane water electrolyzer (AEMWE) device. Monometallic and bimetallic transition metal sulfides (TMS), concerning Ni-, Co- and Mo-based materials, were hydrothermally synthesized and physicochemically characterized. Electrochemical studies evidenced a synergistic effect arising from the association of 2H-MoS2 phase with a second metal compound. Such synergy was attributed to the cobalt and nickel ability to dissociate water, contrary to MoS2, which is a necessary step in alkaline media. Despite that, nickel molybdenum sulfide (Ni0.5Mo0.5Sₓ) and cobalt molybdenum sulfide (Co0.5Mo0.5Sₓ) showed to have their HER kinetics limited by their conductivity. This issue was overcome by adding Carbon Vulcan XC72R in the ink formulation, which led Co0.5Mo0.5Sₓ and Ni0.5Mo0.5Sx to deliver a current density of 200 mA cm-2 at overpotentials only 66 and 60 mV higher than 40 wt.% Pt/C, respectively.Besides that, an exploratory study of ink formulations replacing Nafion® ionomer by the Sustainion® XB-7 one was provided, applying Ni0.5Mo0.5Sₓ as catalyst. It was verified that, to maintain a comparable activity, ionomer content must be reduced, and the solvent ratio also needed to be regulated; higher volume of isopropanol than water was required. It highlights how unique is the catalyst/ionomer interaction and shed light on the importance of studying it.Finally, an AEMWE single cell was constructed by applying Co0.5Mo0.5Sₓ, Sustainion® X37-50 and Ir black, as cathode, anion exchange membrane and anode, ...
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